Ages and Blood Ties
by kuraikitsune13
Summary: AU. Marceline is a university student who fell in love with not only a man that is four years younger than her, but is unfortunately also her cousin; Finn. She planned to keep all her feelings to herself, when one day, Finn bought home a girl with him and she was apparently his girlfriend. What will she do now?
1. Chapter 1

**Author's Note: Hhhh- Hello everyone. It's been awhile, yes. And my hiatus accidentally went a bit more than a month, lol. But to compensate, here's a short Finnceline story. Now, the topic touched on here is going to be a bit controversial, (As if a relationship between an older woman and a younger man isn't controversial enough lol) since other than being a story about a younger man and an older woman, it also touches on cousin love. Yes. Love between cousins. Now, I know that some of you might be wanting to bail right now, but, before that, please take note that is is actually legal. They do not share the same parent(s) with you. So it's totally legal. Totally. Not incest at all. Jeez. Anyways, it's gonna be rather short, and I've written it all out, except that I'm posting it into several chapters, since, why not. Also, it's gonna be in a AU, or Alternate Universe, where all of them are normal humans. (I believe this was called the 'Domestic AU'...? Gosh, I don't know these kind of things lmao) Soooo yeah. Do enjoy.**

**Disclaimer: I do not own Adventure Time.**

* * *

**Part 1.**

"Hey Bonnie," Marceline casually greeted her cousin who was casually lying down on a sofa.

"Hey," she replied back with the same tone, her eyes, glued onto the television before her. Both of them remained silent after that, their eyes, intent on the moving pictures on the screen.

* * *

Marceline is a second-year student in a rather prestigious arts and music University that she had somehow managed to enter. She had gone through a lot so far in the beginning of the semester, but now she's currently in her mid-semester break, which would last for around two weeks, and had decided to bunk in at her maternal aunt and uncle's house which was much closer to her University compared to her own home.

While others might see this as an innocent act of a niece wanting to stay at a relative's home, her true intentions were something else. The actual reason on why she was so willing on spend her vacation there rather than back at her Dad's was because of a certain boy that she has her eyes on. Of course, none of her relatives knew about this, because if they do, they would possibly disallow her from staying with them anymore.

Okay, most of you might be wondering right now; why would her relatives react in such way just because she had her eyes set on a boy?

Well, the answer may be-

"Hey, Marcy!"

Marceline's head quickly turned towards the direction of the voice. The voice of the person that she had sooooo wanted to see, especially since it's been awhile. Though, before answering, she took a quick glance of that person, from top to bottom, just to take in their beautiful form and embed the memory into her head. Their soft, shoulder-length blonde hair; their calming, sky-blue eyes, and their tall and lanky feature with all its boyishness. Her heart was beating so fast at the sight, as it had been a sight that she had been yearning to see after all the stress that she'd gone through in University. She had missed him so much. But then, she casually replied back, "Hey, Finn."

_Calm demeanour, calm demeanour, _she silently chanted in her head, as the boy then proceeded to plonk himself right next to her and join her and his sister in watching the telly.

Yep. His sister. Bonnie is his sister. Her cousin. In other words, he is her cousin as well. She is in love with her own cousin.

_Stupid Marcy, _she then, noiselessly cursed to herself.

It was bad enough that their age gap is quite wide, but it gets worst when he is her cousin.

* * *

Marceline first realized that she had feelings for the boy back when she was 18 (while he, himself is 14). She was recovering from heartbreak; the man she used to like was an asshole. But then Finn came, suddenly showering her with kindness that she hadn't felt for a very long time, especially from a man. However, it took her awhile to then, realize, that he had always been a kind boy in general. This fact made her feel a bit sad, as the kindness was not specifically for her, but she got over it, while at the same time, keeping her feelings for him intact.

While most people would probably want their feelings to be responded to (or at least express their feelings once before knowing that the person they love do not feel the same); Marceline, instead, was the type to remain silent when it comes to her emotions. She _would _express anger, or happiness, or sometimes even sadness, but love? Nah, she'll keep quiet about that.

Now, that habit of hers, to keep silent about her feelings of love, fits perfectly in her current situation, from which she had to zip her mouth from blurting out anything that can expose her feelings for Finn, her own cousin bro. While certain societies totally allow cousin relationships or marriages, the society that she's currently in sees cousin relationships and/or marriages as a social stigma, and anything that might happen between Finn and her would be strongly opposed by many. While Marceline is willing go through oceans of lava just to save her relationship with someone, it is quite impossible to do so when there's a constant nagging in her head that kept telling her about the pain of rejection.

_Finn and I are never gonna be together, _was what it kept saying. How can she save a relationship when she doesn't even have one? That idea kept getting stuck in her head, and therefore, she never made a move on him.

After a few days of her stay, however, she started regretting her life decisions. Finn came home with a girl, perky, bright-eyed, and totally in the same age as he is. At first she felt betrayed. She thought that Finn doesn't want to be in relationships...? Or at least that was what Bonnibel told her. But it turned out that he wanted to have a girl after all, huh.

* * *

**So, that's all for part one. Shall be uploading more in two or three days. To Be With Her shall come up soon (hopefully), once I force myself to get the future chapters done. What did you think of this story so far? Too weird? Too uncomfortable? Do tell me in the reviews~!**


	2. Chapter 2

**Author's Note: Sorry for lateness hhhhh- I haven't even updated To Be With Her as well. Sorry, y'all. I'll try to update today, promise. Here's the second chapter for this story. This story is kinda short, btw. Just so you know. Posting it in short chapters due to this reason. XDD At first I thought of posting it in one whole chapter and making it a oneshot, but I'm still revising on the ending bit of this story, so I decided against that. The earlier parts are already okay though, so yeahh.. Anyways, hope you enjoy today's chapter.**

**Thanks for the reviews given on the previous chapter, btw! **

**Disclaimer: I do not own Adventure Time.**

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"I don't like her," Bonnibel softly whispered, as the both of them sat in the dining room while Finn and his new girlfriend took the whole living room for themselves.

Marceline looked up from her sandwich, her eyes widening slightly upon hearing Bonnibel's sudden confession.

"It's not because I have a sister-complex or something like that," she continued. "I know that I'm overly clingy when it comes to Finn sometimes. But this girl, she just... She challenges me."

"What do you mean?" Marceline asked, clearly confused with her cousin's words.

"Well... I just find her...really annoying...," the other girl replied, seemingly choosing her words carefully. "She likes to butt in to our family's business, every single one of them. And she and Finn had only been together for like, a week or so."

"Wow," was Marceline's only reply.

"I just hope...," Bonnibel pressed on, "that Finn would quickly open his eyes and dump her ASAP... He deserves...much more than _that._"

At this, Marceline remained silent, and simply nodded. She then, took another bite of her sandwich.

* * *

"Is she really your girlfriend?" Marceline asked Finn, as she watched him playing Skyrim on his Xbox. The blonde never answered, so she had to let a full ten minutes pass before she ask him again, this time with a more playful tone in her voice.

"So, she really your girlfriend eh? Eh? Eh? C'mooonn, answer to me ya brat."

Finn smiled a bit, at her attempt to lighten her mood, before answering to her, "Yes..."

?

Marceline never said a word after that, and continued watching the boy play his game. Truth be told, she actually felt some form of uncertainty hanging in his tone when he answered her. Though, she was pretty sure that it was only her imagination, trying to soothe the pain that was beginning to bud deep inside her chest.

* * *

The girl came again the following day.

And gosh, Bonnie was right; she really does like poking her nose into other people's business.

Marceline was making lunch for the family (a form of payment, she supposed, since she's lodging for free at the place) when the blasted girl suddenly burst into the kitchen and insist on doing everything. This, of course, led to the lateness in preparing food since she wasn't that good of a cook, and was painfully slow at doing things as she kept picking up her phone and chat with her friends, much to the older woman's chagrin.

What angered her more, however, was the fact that Finn let the whole ordeal happen right before his eyes. He didn't even try to stop his stupid girlfriend, he didn't try to explain to her that some things must be done in a hurry; he didn't even say a word and just walked away from the whole scenario. It pisses her off greatly, upon seeing such submissive behaviour come from him. A brave, kind boy who usually expresses out his thoughts like him, to be reduced to nothing but a puppet before a girl that he'd just recently been in a relationship with.

Fed up, Marceline rushed up to her room (a.k.a. the guest room), not bothering on lunch at all, and in a hurry, began packing her bags. She didn't come to her aunt and uncle's house for this. She came to relax. To calm her nerves after all the studying that she had done. To see Finn's face and feel the constant burning fire in her chest be reduced to mere ashes, and then transform into in a beautiful phoenix that would soar freely and happily among the crevices of her heart. But no. Instead of being able to feel all that, she was instead forced to confront an annoying brat that is a total stranger to her and yet has forced its way into her life like a horrible flu.

Marceline slammed her small baggage close as the final thought pass through her head, and felt a warm liquid slip through her eyes, and down across her cheek. Confused, she pulled up a finger to her face, and caught the liquid that was threatening to drop from her chin. She then, looked at her finger, the one which she had used to pick up the liquid, and stared at it for a very long time.

It was then when she finally realize, that she was jealous after all. She was jealous, and angry at the fact that Finn, the boy that she really, really liked, albeit being her own cousin, took in a girl as horrible as this to be a special someone. If the girl were to be someone really nice, she didn't think she'd mind, but, this girl is just...

Unable to comprehend her feelings any longer, she burst into silent tears, noiselessly weeping at each broken piece of her heart. She's jealous that the girl gets the person that she wants, though at the same time, she was angry that the same person had done a really _shit _job at finding a girl. These feelings that overwhelmed her broke her already broken heart into smaller bits and pieces, making it more difficult to repair. Heck, in fact, the person whom she expects to repair it is no longer there, since he now belongs to someone else.

Sighing, she collected herself, cleaned her face, and stormed back down to leave the house for good. As she was walking to the exit, she caught the sight of Bonnibel, yelling at the girl for whatever reason, together with Finn who seemed to be trying to restrain her. She huffed, determined on not caring and simply walked out, back to her dormitory, where she would lament in her self-pity all by herself.

* * *

**So! That's all for now. What did you think of it? Still too weird and disturbing?**

**Tell me in the reviews! XDDD**


	3. Chapter 3 Final

**Author's note: After many days of deliberation, I've finally decided to upload the last part of this short story. So, here you go! The ending of my most controversial story-thing that I've ever written. XDD **

**Enjoy the ride~!**

**Special reply to The Nephilim King Michael: Bruv, Finn's girlfriend in this story has no name. XDD**

**Unbeta'd**

**Disclaimer: I do not own Adventure Time.**

* * *

"That's it, I have enough...!" Finn suddenly exclaimed. He grabbed his girlfriend by the wrist, pulled her to his house's exit, and shoved her out – a literal shove, that almost make her fall to the ground.

"F- Finn?" the girl asked, with plain confusion in her expression.

"You might think that I haven't realized this, but I have," he muttered. "You're terrorizing my family. I told you I wanna keep this whole relationship thing light, but, you're going overboard."

"W- what are you saying?" she questioned again, a look of panic starting to form in her countenance.

"I'm breaking up with you, that's what I'm saying," he replied back, this time, louder, with more strength to his voice.

The girl became silent at this, and after a long pause, she said to him, bitterly, "You hang onto your family too much. You're never gonna get another girlfriend because of this. I'm gonna tell everyone at school that you're such a family baby since you prefer them more your own girl."

With that, she stuck a tongue at him and simply left.

"Ugh, good riddance," Bonnibel groaned, as she approached Finn, pulled him into the house, and slammed the door shut. "She was giving me a major headache... Now we gotta remake lunch... Or get onto dinner, even. Stupid wench, wasting people's time. Anyways, you go and check on Marcy, Finn. I think she got upset when _little miss bossy-pants_ forced her off the kitchen. I'm gonna go do some clean up."

Finn nodded and proceeded to go up the stairs and towards the guest room to check upon his cousin.

"Marcy?" he asked, knocking on the door. There was no answer, so he knocked harder. "Hey, you okay in there? Can I come in...?"

Still silence.

Finn sighed as he rests his head onto the door, and drew circles onto it using his finger.

"Hey... I'm sorry, for all that... Must've been a shit stay for you this time, huh..."

No answer.

"I didn't know what came up to me... when I said 'yes' to her..."

Still no answer.

"I knew that we weren't... suitable... She's always so noisy and stuff... and I'm the quiet guy..."

Dead silence.

"It was peer pressure, I guess... Kids at school were saying that we look good together..."

Nothing.

"...I should've waited for you to get back... right, Marcy...?"

No one.

"Marcy...?"

Finn decided to open the door anyways, due to her constant silence, which was uncharacteristic of her, only to reveal an empty room that looked as if no one had used it (Marcy probably cleaned it up before leaving). Eyes widening, he then, realized, that she must've been affected by the whole ordeal more than he knew. Then, instinctively, he rushed out of his home and instantly caught himself a cab.

* * *

Marceline had been lying on her bed for almost two hours. She had been doing so ever since she arrived back to her room. The whole dormitory is almost empty now, almost everyone have gone back to their homes or something. And then there's her, the person who ran away from a home-like place. She wondered what her uncle and aunt would think of such behaviour. She should've told them first... But since she was being too impulsive, she totally forgot about them and just up and left in the heat of the moment.

_Sniff,_ she heard herself sniff, as she wiped her wet nose. She'd stopped crying a long time ago, but the aftermath of it was still there. If she were to look into a mirror, her eyes and lips might still be all red and puffy.

_What a gross face, _she suddenly interrupted her jumbled-up train of thoughts, as she began to imagine her puffy, red face. This made her giggle a little bit, a small unfunny humour just to cheer herself up a bit. After awhile, she then yawned, a decided to let herself drift into slumber.

_Knock knock knock!_

Marceline opened her eyes, feeling grumpy upon being rudely interrupted from her much-needed slumber. She was about to decide on ignoring it anyways when a familiar voice made her jump out of her skin, almost literally.

"F- Finn...?" she croaked, her voice barely coming out since she'd only recently wake up.

"Marcy!" the familiar voice again, repeated itself, calling out for her name.

She couldn't believe her ears. No, it can't be. Why is the kid here? Is she dreaming?

Still confused, she slowly rose from her bed and hesitantly stumbled towards her door.

"Marcy, open up! I know you're in there!"

The familiar voice was getting more desperate, while her heart began to accelerate in anticipation of seeing his face once she opens that very door.

Her shivering hand clumsily fumbled with the lock, and when she finally unlocked it, she stepped away from the door, not wanting to open it, to welcome the person whom she wanted to see so very much, in.

However, before she knew it, the door burst open, revealing the blond-haired boy with calming, blues eyes, which were at the moment, not-so calm. He was staring at her, his expression, wild and his body, sweaty.

"I- I got lost-," he breathed, "which is why it took me so long-"

"F- Finn," Marceline was about to say, but her words were suddenly stopped by a pair of lips that came crushing onto hers.

* * *

He couldn't believe it. He's kissing her, his own cousin, who is older than him by four years. He didn't know what sort of madness led him into doing so, but it was already too late to pull everything back, he was already kissing her.

He might seem bold right now, to suddenly go to her and smash his lips onto her. But in all honesty, he's scared. She might as well slap him right now. Any time now. Heck, maybe a punch, even. She's a strong lady after all.

However, instead of receiving the painful slap or punch that he was expecting to receive, a pair of arms slid past his neck instead, and pulled him into a hug, while at the same time deepening his kiss with the girl in front of him. At this gesture, he internally sighed in relief, and placed his lanky arms around the older woman's body to also, pull her into a hug.

* * *

Both of them are lying on Marceline's single bed now, cuddling. Nothing really happened after the kiss. They just pulled away from each other after some minutes, and then Marceline cried a bit, out of happiness. But that's all there is to it.

"How long?" Finn asked, as he stared at the plain white ceiling while caressing the older woman's hand that was snugly placed onto his chest.

"Ever since you got your puberty, I guess," she answered, a playful tone in her voice.

"So you didn't like me back when I was a kid?"

"Oh please, you were an annoying brat."

Both of them giggled at this, reminiscing their childhood while they enjoy each other's company. Then, with a more serious tone, Marceline gave him a more proper answer, "...You are so kind to me, that's why... In my life...kind men are like an almost-extinct species. And suddenly, there's you. I mean, you have your own quirks, getting angry and stuff, but, the reasons on why you did such thing were mainly because of your own kindness..."

Finn didn't reply at this, but remained silent for a long period of time instead. Marceline had call out for him in order to elicit a response. Then, after a moment of hesitation, he replied,

"I'm not really kind, Marcy..."

"Hm?"

"I'm... I'm a brat. I'm literally a brat. I'm just a kid, Marcy. What do I know about being kind and all that."

Marceline kept quiet at this, a silent gesture, telling him to continue.

"I... I do bad stuff too. Bad stuff that men do. I'm not perfect for you, this kindness of mine, it might not even last long. When I get older, maybe, suddenly, I turn into an asshole? I- I don't know, I just... Marcy, I..." Finn turns around to lie on his side, so that he can look into the woman's eyes properly.

"...Yes?"

"It might sound stupid for a brat to say this, but, I worry...for your future...if you were to be with me..."

At this, Marceline gave him a small smile and a peck on his lips.

"Silly, let's worry about that together instead of worrying by your own."

Then, she gave him another kiss, but deeper. She felt Finn's body giving a small jolt upon this action, but then she felt him relax as he kissed her back, holding her tight.

"I guess we just have to wait what the future has for us," Finn finally said, after they separated from each other.

* * *

"Gosh, Marcy, stay still," Bonnibel demanded as she tried fixing the makeup on Marceline's face.

"But I'm too nervous!" she replied, as she tapped her fingers onto her knees.

"It's all going to be fine," the other woman reassured her. "Now stand up."

Marceline did as told and stood up. She was clad in a simple white dress that was minimally decorated. Her long, raven hair was decorated with sprinkles and snowdrops, those small white flowers, shining white in the darkness.

Bonnibel stood back to admire her work.

"Damn, guuuurl you look amazing!" she exclaimed, as she pulled out a camera and took a candid photo of her cousin. It was then; she realized that the woman looked rather sad.

"Hey...are you worried about my parents?" the brunette asked.

"Yeah," was her simple reply. "At least my dad is here, though. Heheh."

Bonnibel took Marceline's hands into hers and squeeze them.

"Once you and Finn give them grandkids, they are sooooo gonna accept you guys," she jokingly said, though at the same time, in a reassuring tone. Her cousin giggled and blushed upon hearing this, and light-heartedly scolded her for saying such things.

"Is my baby girl ready?" Marceline's dad suddenly came into the room, surprising them both.

"Geez, dad! At least knock first!" Marceline breathed, still feeling shocked.

"Aww, did I scare my little girl?" The raven-haired scoffed at this. "Now c'mere. Let me take a good look at you"

He took a very long look at his daughter, before expressing on how proud he is, of her.

* * *

The marriage was small, there weren't much people. But it was magical to both Finn and Marceline nonetheless. Ever since that day, they had been together for seven years. Seven years of fighting for their love, and now they can properly seal it. It felt so dream-like, so beautiful; it was almost like it was unreal. But when they pulled each other's cheeks and felt the pain, they knew it was real.

They might be cousins, and in some parts of the country, it is a social stigma. But there's nothing wrong with marrying a person who only share a quarter of your genetic information, is there? It's not like they're _actually_ siblings, after all. What's important is that they love each other, and is willing to go through this harsh world together. That's all that really matters.

End

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**What a cliche ending... =_= This is why I was deliberating on submitting it. XDDD**

**Oh well, thanks to those who read this, thank you very much~! **

**And thanks for keeping up with my weirdness as well! **

**Hope you enjoyed the ride~!**


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